• Journal of the Korea Convergence Society
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• v.10 no.12
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• pp.429-436
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• 2019

This study used raw data from the 2013-2015 National Health and Nutrition Survey, and conducted a multivariate logistic regression analysis to identify factors related to teeth extraction from Korean elderly aged 65 and older (4.037). As a result, the risk of tooth extraction was 1.84 times higher in males, 1.52 times in age 75 or older, 2.36 times higher in income, 2.04 times higher in income, and 1.44 times higher in smokers. The results were statistically significant as 1.49 times without oral examination and 2.30 times without dental treatment for 1 year. Through this, the current health behavior and oral health behavior can reinforce the basis of risk factors related to the need for tooth extraction. At the national level, we need to look for diversification.

• Journal of Technologic Dentistry
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• v.33 no.1
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• pp.25-35
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• 2011

Purpose: There are some advantages of the acrylic resin denture base ; appropriate strength, volume safety, simple processing apparatus, and low cost. But, it have a weakness for fracture by intense pressure or shock. However, the repairs for resin denture base are possible using various materials and techniques. There is a few studies in repairs for resin denture base, but not clinical researches. And there is no studies in absorbed saliva into the region of fracture and bond strength. This study is to observe re-bond strength of resin denture base after repairing under saliva absorption. Methods: The samples were made of heat curing resin and the rectangular parallelepiped specimens which were 50mm long, 10mm wide and 3mm high. The four different groups immersed in the artificial saliva for 2 weeks were prepared, 1) no repaired control samples, 2) immediately repaired samples, 3) repaired samples after 1 day dry, and 4) repaired samples after 3 days dry. The prepared samples were repaired by two different curing materials, self curing resin and heat curing resin method. Each groups composed of 10 specimens were experimented with the three point bending tests for bonding strength measuring Results: There were under condition absorbed in the artificial saliva and repaired by self curing resin method, repaired specimens after 1 day and 3 days dry groups had higher values of bonding strengths than control group, and bonding strengths of immediately repaired samples were similar to those of control samples (p<0.05). There were under condition immersed in the artificial saliva and repaired by heat curing resin method, immediately repaired samples showed similar values to bonding strengths of control groups, and repaired samples after 1 day and 3 days dry groups were lower than those of control group (p>0.05). Conclusion: In this study, the repairs for resin denture base were remarkably high values of bonding strengths than those of the past, and showed that have stable bonding strengths independent of saliva absorption of denture base, so present repairs for resin denture base can be performed, regardless of saliva conditions.

• Journal of Technologic Dentistry
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• v.14 no.1
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• pp.67-79
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• 1992

This study was conducted to analyze the dental care utilization pattern of the city residents. An interview and questionnaire survey was carried for 1008 people who lived in Kimchun-city, Kyungsangpook-do, from february 1 to March 30, 1992. The summarized results are as follows : The rate of persons who experienced the oral disease was 32.7 per 100 persons during 1 year and it was highest in the age group of 20$\sim$29. During 1 year period, 90.3% of the cases had treated the perceived oral disease, 9.7% had done no action. 65.8% had treated experienced oral disease at dental clinics. The rate of person who dad experienced dental prosthesis during ten-year period was 37.5% among 18year and older, and it was higher in male as compared to female and it was highest in age group of 40$\sim$64 year old. The rate of person who had treated dental prosthetics by the unauthorized illegally was 27.0%, and the reason for it was cheap-price free(44.2%). Of the person who dad treated dental prosthetics by the unauthorized illegally, 64.3% had satisfied and 4.3% had done out of use, while each was 80.1%, 2.7% at dental clinics. The rate of persons with missing teeth was 18.0%. Of the persons with missing teeth, 57.6% did not treat the missing teeth due to economic reason and 89.6% hopped treating the dental prosthetics at dental clinics. In consideration of above finding, we may conclude that oral health community program to prevent oral diseases should be intensified, oral health education to raise oral health knowledge should be performed periodically and the control of unlicensed activities should be enforce at community health center and allows benefits for prosthetics.

• Journal of Korean Dental Hygiene Science
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• v.6 no.2
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• pp.1-12
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• 2023

Objectives: This study attempted to identify the eating habits and oral health behaviors of Korean teenagers, studying their relationship with oral health status. The findings serve as fundamental data to enhance proper eating habits and oral health-related projects, ultimately improving teenagers' oral health. Methods: It was analyzed through the original data of the 16th (2020) online survey of youth health behavior in Korea, Frequency analysis, complex sample cross-analysis, complex sample logistic regression analysis were conducted using the SPSSwin 21.0 program. Results: As a result of the study, was associated with the consumption of all sweet drinks, fast food intake, and the frequency of daily brushing over the past 7 days Teeth pain is noted with the consumption of soda, sweet drinks, fast food, and the frequency of daily brushing over the past 7 days. Gum bleeding is noted with the consumption of sweetened products, fast food intake, and the frequency of daily brushing over the past 7 days. Conclusions: Eating habits and oral health behaviors should be considered for the oral health management of middle and high school students. Specific measures should be sought to provide proper dietary education and systematic oral health education to improve the oral health of middle and high school students.

• The Journal of Korean Society for School & Community Health Education
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• v.9 no.2
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• pp.15-31
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• 2008

Objective: This study is a quasi-experimental study by nonequivalent control group pretest-posttest design, performed in order to identify whether the program developed on the basis of Ajzen(1988, 1991)'s theory of planned behavior (TPB) for predicting the safety behavior of students of department of dental technology affects intention toward safety behavior and general behavior. Therefore, the purpose of this study is to identify whether the safety education in laboratories in which knowledge is reinforced on the basis of the TPB theory affects safety behavior. Methodology: The theoretical framework of this study was established on the basis of the TPB by Ajzen(1988, 1991). This study was performed between May 20 and December 5, 2006, and the subjects included 101 in the experimental group and 98 in the control group, a total of 199. The experimental group was educated through six 50-minute sessions (twice a week) for three weeks. The experimental group was pretested, educated, and then asked to answer the pro-questionnaire after finishing the sixth session, but the control group was free from intervention. The research tool in this study was developed by the authors with reference to the process of tool development used in Schifter and Ajzen (1985) based on Ajzen and Fishbein(1980)'s tool development guide. Results: The data were analyzed through SPSS 14.0 version. The reliability test of attitude, subjective norm, perceived norm, intention, and behavior toward safety behavior as TPB variables was calculated of Cronbach's alpha coefficient, and general characteristics and the homogeneity test of the experimental and the control groups were analyzed through t test and $X^2$ test. According to the results of the analysis, the experiment group may be higher than the control group after the safety education in the scores of attitude, the subjective norm, the perceived norm, and the intention toward safety behavior as TPB independent variables showed no significant difference, but there was significant difference in the behavior and the knowledge. Meanwhile, according to the results of the pretest and posttest, eleven items in the experimental group and two items in the control group showed significant difference in the behaviors, and twelve in the former and four in the latter were significantly different in the knowledge. Conclusion: The safety education program developed on the basis of TPB was identified to enhance safety behavior and knowledge. Therefore, the safety education program used in this study for students of department of dental technology may be utilized as database for safety education in the department of dental technology.

• Journal of Environmental Health Sciences
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• v.32 no.6
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• pp.556-559
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• 2006

This study was performed to investigate the levels of cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) in water and rice samples taken from five sites on a stream used for agricultural water in the Jeon-buk area, Korea. The water samples were randomly collected by the recommendations of the World Health Organization, and rice samples were randomly collected from rice paddy. The water and rice samples were analyzed by the recommendations of Food Code of Korea and using inductively coupled plasma spectrometer. Although there was variation between sampling sites, the levels of the metals in rice were on average much higher than those in water. The ratios of metal levels of rice to water were: $8.0{\sim}35.4\;for\;Cd;\;2.2{\sim}7.2\;for\;Cu;\;5.9{\sim}18.3\;for\;Pb;\;and\;10.6{\sim}75.7$ for Zn. These results suggest that there were transfer and bioaccumulation of the metals from the water to the rice taken place.

• Journal of Embryo Transfer
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• v.27 no.4
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• pp.205-209
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• 2012

Transgenic rats and mice are useful experimental animal models for medical research including human disease model studies. Somatic cell nuclear transfer (SCNT) technology is successfully applied in most mammalian species including cattle, sheep, pig and mouse. SCNT is also considered to increase the efficacy of transgenic/knockout mouse and rat production. However, in the area of reproductive biotechnology, the rodent model is inadequate because of technical obstacles in manipulating the oocytes including intracytoplasmic sperm injection and SCNT. In particular, success of rat SCNT is very limited so far. In this review, the history of rodent cloning is described.

• Journal of Technologic Dentistry
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• v.31 no.2
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• pp.23-30
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• 2009

All-ceramic restorations have gained acceptance among clinicians and patients because of their superior esthetics. Most all-ceramic systems have a 2-layer structure, using a weak veneering ceramic over a strong supporting core. often, failure of all-ceramic restorations occurs when the veneering ceramic fractures, exposing the core material. The purpose of this study was to compare the shear bond strength of heat press ceramic system (Zirpress) to zirconia core with various surface treatments. 10 metal cores and 50 zirconia cores were fabricated and divided into six groups according to surface treatment such as Zirliner application, aluminium oxide blasting, and 9.5% HF etching. Sixty specimens were prepared using Zirpress, veneered 8mm height and 3mm in diameter, over the zirconia cores (n=10). The shear bond strength test was performed in a universal testing machine with a crosshead speed of 1/min. Ultimate shear bond strength data were analyzed with One-way ANOVA and the Scheffe's test (p=.05). Within the limits of this study, the following conclusions were drawn: The mean shear bond strengths (MPa) were: 12.93 for $110{\mu}m$ aluminium oxide blasting/Rexillium III/IPS e.Max Zirpress; 14.92 for $50{\mu}m$ aluminium oxide blasting ${\pm}9.5%$ HF etching/Zirconis core/IPS e.Max Zirpress; 16.37 for $110{\mu}$ aluminium oxide blasting + 9.5% HF etching/Zirconis core/IPS e.Max Zirpress; 12.89 for $200{\mu}$ aluminium oxide blasting + 9.5% HF etching/Zirconis core/IPS e.Max Zirpress; 19.30 for 9.5% HF etching/Zirconis core/IPS e.Max Zirpress; 19.55 for Zirliner/Zirconis core/IPS e.Max Zirpress. The mean shear bond strength for ZNTZH (Zirliner/Zirconis core) and ZNTEH (9.5% HF etching/Zirconis core) were significantly superior to MS110H ($110{\mu}$ aluminium oxide blasting/Rexillium III) and ZS200EH ($200{\mu}$ aluminium oxide blasting + 9.5% HF etching/Zirconis core) (p<0.05).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.693-700
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• 2020

This study compared the accuracy and reliability of definitive casts fabricated from a digital impression and conventional impression technique. A master model with the prepared upper full-arch tooth was used. Samples of ten plaster models and ten polyurethane models were duplicated using a selected standard master model. Six linear measurements were recorded between the landmarks, directly on each of the stone models and the polyurethane models on two occasions by a double examiner. The Wilcoxon signed-rank test, interclass correlation coefficient (ICC), measurement error (MSE), and limit of agreement (LoA) were used for statistical analysis. The ICC ranged from 0.76 to 0.99 when comparing the stone models and polyurethane models. The mean difference between the stone models and polyurethane models ranged from 0.09mm to 0.20mm, suggesting that stone models might be slightly larger than polyurethane models. Based on this study, the accuracy of the polyurethane models in evaluating the performance of an oral scanner and subtractive technology was acceptable. Further studies will be needed on patient subjects under clinical conditions that may involve missing or malpositioned teeth and fixed dental prostheses because this study was limited to use a standard master model and duplicated sample models in a laboratory setting.

• Journal of Technologic Dentistry
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• v.32 no.3
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• pp.195-207
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• 2010

Purpose: The purpose of this study was to observe the microstructural changes of surface in the specimens, performing the shear bond strength testing. The currently most used non-precious alloys are nickel-chromium based alloys with or without beryllium. However, their biocompatibility has been questioned concerning possible damages to the health of the patient and professionals involved in the fabrication of prosthesis caused by long exposure to Ni and Be. An option to nickel-chromium alloys is the cobalt-chromium alloy, an alternative that does not sacrifice the physical properties of the metal porcelain systems. Studies in the animals substantially show that the cobalt-chromium alloys are relatively well tolerated, being therefore more biocompatible than the nickel-chromium alloys. Methods: Non-addition Be to nickel-chromium based alloy(Bellabond plus) and cobalt-chromium alloy which has been widely used(Wirobond C) fused with ZEO light porcelain classified control group and cobalt-chromium alloy which is developing alloy of Alphadent company in Korea(Alphadent alloy) fused with ZEO light porcelain classified experimental group. The specimens of $4mm{\times}4mm{\times}0.5mm$ were prepared as-cast and as-opaque to cast body to analyze the mechanical characteristic change, the microstructure of alloy surface. The phase change was used to observe through XRD analysis and OM/SEM was used to observe the surface of specimens as-cast and as-opaque to cast body. Chemical formation of their elements was measured with EDS. Then hardness was measured with Micro Vicker's hardness tester. Shear bond strength test thirty specimens of $10mm{\times}10mm{\times}2mm$ was prepared, veneered, 3mm high and 3mm in diameter, over the alloy specimens. The shear bond strength test was performed in a universal testing machine(UTM) with a cross head speed of 0.5mm/min. Ultimate shear bond strength data were analyzed with one-way ANOVA and the Scheffe's test (P<0.05). Within the limits of this study, the following conclusions were drawn: The X-ray diffraction analysis results for the as-cast and as-opaque specimens showed that the major relative intensity of Bellabond plus alloy were changed smaller than Wirobond C and Alphadent Co-Cr based alloys. Results: Microstructural analysis results for the opaque specimens showed all the alloys increased carbides and precipitation(PPT). Alphadent Co-Cr based alloy showed the carbides of lamellar type. The Vickers hardness results for the opaque specimens showed Wirobond C and Alphadent Co-Cr based alloys were increaser than before ascast, but Bellabond plus alloy relatively decreased. The mean shear bond strengths (MPa) were: 33.11 for Wirobond C/ZEO light; 25.00 for Alphadent Co-Cr alloy/ZEO light; 18.02 for Bellabond plus/ZEO light. Conclusion: The mean shear bond strengths for Co-Cr and Ni-Cr based alloy were significantly different. But the all groups showed metal-metal oxide modes in shear bond strengths test at the interface.